What would happen if you were to connect the positive and negative terminals of a cell together without placing a bulb, motor, or some sort of resistance in the circuit?
Answer: If the circuit were left on for more than a few minutes, you’d ruin the cell (and if the current source was large enough, you’d burn yourself or start a fire).
Things Required:
Two “D” cells in battery holders
One torch bulb in lamp holder
Two switches
Connecting wires with each end stripped 1½ inches bare of insulation
Directions:
Assemble the circuit below.
Close only switch A. What happens to the lamp? Is there a closed circuit? If so, trace the complete circuit through which electricity flows.
Close only switch B. What happens to the lamp? Is there a closed circuit? If so, trace the complete circuit through which electricity flows.
Bend the clip in switch A so that this switch may remain on. While the lamp is glowing, close switch B. What happens? What path does the current flow when both switches are closed? Why? Release switch B. What happens now? Why?
This Is What Happens:
Switch A controls current flow in the outer loop. When switch A is closed, current flows along this outer path to light the lamp.
Switch B is part of a separate path that offers no resistance. When switch B was closed, its path became complete. Since the path had no resistors, it acted as a short circuit. The current flowed across switch B and bypassed the lamp. Without any current flow, the lamp went out.
